/*
 * gleem -- OpenGL Extremely Easy-To-Use Manipulators.
 * Copyright (C) 1998-2003 Kenneth B. Russell (kbrussel@alum.mit.edu)
 *
 * Copying, distribution and use of this software in source and binary
 * forms, with or without modification, is permitted provided that the
 * following conditions are met:
 *
 * Distributions of source code must reproduce the copyright notice,
 * this list of conditions and the following disclaimer in the source
 * code header files; and Distributions of binary code must reproduce
 * the copyright notice, this list of conditions and the following
 * disclaimer in the documentation, Read me file, license file and/or
 * other materials provided with the software distribution.
 *
 * The names of Sun Microsystems, Inc. ("Sun") and/or the copyright
 * holder may not be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED "AS IS," WITHOUT A WARRANTY OF ANY
 * KIND. ALL EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND
 * WARRANTIES, INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, NON-INTERFERENCE, ACCURACY OF
 * INFORMATIONAL CONTENT OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. THE
 * COPYRIGHT HOLDER, SUN AND SUN'S LICENSORS SHALL NOT BE LIABLE FOR
 * ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
 * DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL THE
 * COPYRIGHT HOLDER, SUN OR SUN'S LICENSORS BE LIABLE FOR ANY LOST
 * REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL,
 * CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND
 * REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF THE USE OF OR
 * INABILITY TO USE THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGES. YOU ACKNOWLEDGE THAT THIS SOFTWARE IS NOT
 * DESIGNED, LICENSED OR INTENDED FOR USE IN THE DESIGN, CONSTRUCTION,
 * OPERATION OR MAINTENANCE OF ANY NUCLEAR FACILITY. THE COPYRIGHT
 * HOLDER, SUN AND SUN'S LICENSORS DISCLAIM ANY EXPRESS OR IMPLIED
 * WARRANTY OF FITNESS FOR SUCH USES.
 */

package org.gephi.lib.gleem.linalg;

/**
 * Arbitrary-size single-precision matrix class. Currently very
 * simple and only supports a few needed operations.
 */

public class Matf {
    private final float[] data;
    private final int nCol; // number of columns
    private final int nRow; // number of columns

    public Matf(int nRow, int nCol) {
        data = new float[nRow * nCol];
        this.nCol = nCol;
        this.nRow = nRow;
    }

    public Matf(Matf arg) {
        nRow = arg.nRow;
        nCol = arg.nCol;
        data = new float[nRow * nCol];
        System.arraycopy(arg.data, 0, data, 0, data.length);
    }

    public int nRow() {
        return nRow;
    }

    public int nCol() {
        return nCol;
    }

    /**
     * Gets the (i,j)th element of this matrix, where i is the row
     * index and j is the column index
     */
    public float get(int i, int j) {
        return data[nCol * i + j];
    }

    /**
     * Sets the (i,j)th element of this matrix, where i is the row
     * index and j is the column index
     */
    public void set(int i, int j, float val) {
        data[nCol * i + j] = val;
    }

    /**
     * Returns transpose of this matrix; creates new matrix
     */
    public Matf transpose() {
        Matf tmp = new Matf(nCol, nRow);
        for (int i = 0; i < nRow; i++) {
            for (int j = 0; j < nCol; j++) {
                tmp.set(j, i, get(i, j));
            }
        }
        return tmp;
    }

    /**
     * Returns this * b; creates new matrix
     */
    public Matf mul(Matf b) throws DimensionMismatchException {
        if (nCol() != b.nRow()) {
            throw new DimensionMismatchException();
        }
        Matf tmp = new Matf(nRow(), b.nCol());
        for (int i = 0; i < nRow(); i++) {
            for (int j = 0; j < b.nCol(); j++) {
                float val = 0;
                for (int t = 0; t < nCol(); t++) {
                    val += get(i, t) * b.get(t, j);
                }
                tmp.set(i, j, val);
            }
        }
        return tmp;
    }

    /**
     * Returns this * v, assuming v is a column vector.
     */
    public Vecf mul(Vecf v) throws DimensionMismatchException {
        if (nCol() != v.length()) {
            throw new DimensionMismatchException();
        }
        Vecf out = new Vecf(nRow());
        for (int i = 0; i < nRow(); i++) {
            float tmp = 0;
            for (int j = 0; j < nCol(); j++) {
                tmp += get(i, j) * v.get(j);
            }
            out.set(i, tmp);
        }
        return out;
    }

    /**
     * If this is a 2x2 matrix, returns it as a Mat2f.
     */
    public Mat2f toMat2f() throws DimensionMismatchException {
        if (nRow() != 2 || nCol() != 2) {
            throw new DimensionMismatchException();
        }
        Mat2f tmp = new Mat2f();
        for (int i = 0; i < 2; i++) {
            for (int j = 0; j < 2; j++) {
                tmp.set(i, j, get(i, j));
            }
        }
        return tmp;
    }

    /**
     * If this is a 3x3 matrix, returns it as a Mat3f.
     */
    public Mat3f toMat3f() throws DimensionMismatchException {
        if (nRow() != 3 || nCol() != 3) {
            throw new DimensionMismatchException();
        }
        Mat3f tmp = new Mat3f();
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                tmp.set(i, j, get(i, j));
            }
        }
        return tmp;
    }

    /**
     * If this is a 4x4 matrix, returns it as a Mat4f.
     */
    public Mat4f toMat4f() throws DimensionMismatchException {
        if (nRow() != 4 || nCol() != 4) {
            throw new DimensionMismatchException();
        }
        Mat4f tmp = new Mat4f();
        for (int i = 0; i < 4; i++) {
            for (int j = 0; j < 4; j++) {
                tmp.set(i, j, get(i, j));
            }
        }
        return tmp;
    }
}
